1. Field of the Invention
The present invention relates generally to a data backup apparatus utilized in an electronic control system, and more particularly to a data backup apparatus, for example, utilized for a failure-diagnosis apparatus in which pieces of diagnosis data required for the analysis of an unusual condition in on-vehicle equipment are stored and read out to perform a failure-diagnosis of the on-vehicle equipment. Also, the present invention relates to a data backup method for storing the diagnosis data utilized for the failure-diagnosis of the on-vehicle equipment in the data backup apparatus.
2. Description of the Related Art
A data backup apparatus in an electronic control system has been conventionally utilized for a failure-diagnosis apparatus in which pieces of diagnosis data required for the analysis of unusual conditions in on-vehicle equipment are stored. That is, as is described in the Japanese Published Unexamined Patent Application No. 142849 of 1987 (S62-142849) as an example, in the failure-diagnosis apparatus, pieces of diagnosis data transferred from various on-vehicle parts are stored in a backup memory of the data backup apparatus at previous intervals regardless of whether the electric power is cut-off the most recent diagnosis data replaces pieces of previous diagnosis data at the previous intervals, and a failure-diagnosis of the on-vehicle parts is performed with the updated diagnosis data to check whether or not a failure condition exists in the on-vehicle equipment.